US2400344A - Electromagnet - Google Patents

Description

May 14, 1946.

J. F. FRESE 2,400,344 ELECTROMAGNET Filed Sept. 17, 1943 s Sheets-Sheet 1 H9 1 Fig 2 I TOR.

May 14, 1946. FREQ; 2,400,344

ELECTROMAGNET Filed Sept, 17, 1943 s Sheets-Sheet 2- IN V EN TOR.

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May 14, 1946. F, FRESE 2,400,344

ELECTROMAGNET Filed Sept. 17, 1943 3 Sheets-Sheet 3 Patented Mai, 1946 UNITED STATES PATENT OFFICE ELECTROMAGNET' Joseph F. Frese, Baltimore, Md.

Application September 17, 1943, Serial No. 502,803

(Cl. 175-336) v 3 Claims.

This invention relates to electromagnetically operated switches of the type wherein the magnet comprises a hollow field piece with the magnetizing coil arranged within the fiield piece. Th invention comprises variou features of construction which facilitate the assembling and taking apart of the various parts of the switch and which increases its efliciency and it also includes means whereby when two similar switches are arranged adjacent one another it is impossible to close either one of said switches while the other is closed. The details of construction of the switch mechanism will be clear from the following description, taken in connection with the accompanying drawings in which Figure 1 is a front view of two similar electromagnetic switches with an interlocking device which prevents the closure of either switch while the other switch is closed, the magnet coils being shown in dotted lines;

Figure 2 is a side view of the same, looking from left to right in Figure 1;

Figure 3 is a section on the line 33 ofFig- I ure 4;

Figure 4 is a front view, on a'larger scale, of the electromagnet, and movable contact carrying member shown in the upper part of Figure 1, the magnet coil being shown in dotted lines;

Figure 4* is a side view of one of the contact assemblies, 2. part of the contact carrying bar being shown in section on the line .ra: of Figure 4;

Figure 4 is a plan view of one of the contact members;

Figure 4" is a plan view of one of the metal blanks from which the housing for the contact and spring is formed;

Figure 5 is a front view of one of the magnet field pieces;

Figure 6 is a perspective view of the hollow coil which fits within the hollow field piece;

Figure '7 is a bottom plan view of the field piece with the shading coil and interlocking guides its supporting links, one of the latter being shown partly broken away; 4

Figure 13 is a partial section on the line |3-|3 of Figure 12, and

Figure 14 is a side View of the pivot pin which connects the armature with the supporting links.

Referring to Figures 1 and 2 of the drawings, A and B represent two similar electromagnetic switches arranged one above the othe on a base plate I which is adapted to stand vertically. The magnets of the switches are spaced from the base plate by supporting members 3 such as are shown in Frese Patent #2258556, dated October 17, 1941. The lever I, centrally pivoted on a support 4, secured to the base plate, has rollers 2 and l at its ends and these are adapted to engage the ends of the movable contact carriers of both switches and prevent the closure of either switch while the other switch is closed. The operation of this interlocking bar Will be hereinafter described.-

The switches A and B are alike in structure and a description, of one switch will apply to the other. Therefore in Figure 4 is shown an electromagnet with it's armature and the contact carrying member which it operates in the same positions as the armature and contact carrying member are shown in switch A, Figure 1, wherein the armature and said member are shown in the open position of the switch.

Figure 5 shows the field piece a of the magnet, which is a hollow laminated structure of rectangular form, having an opening in the center of its lower wall, forming opposed pole pieces 1), the opening being of suiiicien't width to permit the armature guide, hereinafter referred to, to pass through.

Transverse grooves 5 are formed in the bottom wall of the field pieces, adjacent the ends of the pole pieces, and a shading coil 6, shown in Figure 8, has its side portions 6* embedded in these grooves, as shown in Figure 7, while its end portions 6' are bent upwardly and extend across the gap in the bottom wall of the field piece and spaced a short distance from said wall as shown in Figures 4 and 7. Metal guide straps a, One of which is shown in Figure 9, are secured to the sides of the lower wall of the field piece and these extend across the gap in said wall, as shown in Figures 1, 4 and 7. Each of the metal guide straps g has an opening 8 in its central portion, and, opposite this opening, a lateral projection 9. These guide straps interlock with the armature guide pieces, as hereinafter explained. Metal guide straps h, Figures 1, 3 and 4, are secured to the opposite sides of the upper wall of the field piece in alignment with the guide straps a on the lower wall.

In Figure 10 is shown a guide for the armature comprising two identical complementary section 1 and 1', made of thin resilient non-magnetlzable, metal, such as copper or brass, troughlike in cross section, each section of the guide having a flat central portion In and parallel sidewalls Ill or equal width, extending at a. right angle to the central portion, the central portion being slotted longitudinally, forming a tongue II, the free end of which is turned slightly outward from the plane oi the central portion, as

shown at H. Each section of the armature.

guide has a flange il extending outwardly at a right angle to the plane of its central portion at the end adlacent the free end of the tongue, and in each flange there is a slot i I' adapted to receive the projection 9 on one of the metal guide straps a. The ide walls HP of both armature guide section are cut off at the ends opposite the flange, forming shoulders I2 and leaving narrow flanges l2 at the margins of the central portion extending from said shoulders to the adjacent end of the section.

The armature k, as shown in Figures 11, 12, and 13, is a one-piece structure comprising a core l9, rectangular in cross section and a head H at a right angle to the core, the armature being composed o1 T-shaped laminations. The armature has a transverse bore l'l extending through the central part of its head as shown in Figures 11 and 13, and a pivot pin l6, tapering from its center toward both or its ends, extends through this bore. The pivot pin has pintles at its ends which are iournaled in the lower ends or flat metal links, l5, l5- which connect the armature with the contact-carrying member a when the parts are assembled as shown in Figure 4. Each ture attached are inserted upwardly through the armature guide sections and the upper ends the links are securely fastened to the contact carrying member by the screws l", Figure 4. The

link is provided with screw holes at its upper end through which screws l5 may be passed to fasten the upper ends or the links rigidly to the contact carrying member.

In assembling the parts thus far described, with the field .plece held in a vertical plane, the coil c (Figure 6) is placed within it and the armature guide sections 1 and 7" are then passed upwardly through the gap in the lower wall of the field piece within the guide straps g and it until the shoulders l2 engage the upper wall of the field piece which limits the upward movement of the guide sections. The guide sections extend through the central opening in the coil and hold the coil in place. As each armature guide section approaches its upward limit of movement the end llof its tongue ll enters the slot 8 in the adjacent guide strap a and the projection 9 on said guide strap enters the slot ll in the flange ll" 01' the armature guide section. The engagement of the tongues of the armature guide sections with the guide straps g prevents accidental displacement of the armature sections and the projections 9 on the guide straps serve to hold the armature guidesections in parallel relation.

The short side flanges iron each armature guide section rest against the side oi! the upper wall of the fleld piece where they are retained by a guide strap 11.

After the armature guide sections have been inserted in the fleld piece, as described, the links I! and I! are applied to oppositesides or the armature, with the ends 01 the conical pivot pin l9 extending into the perforations in the lower ends of the links. Then the links with the armalinks fit freely within the armature guide and the armature, because of its pivotal connection with the links, has a limited rocking movement so that its head can make a fiat contact with the lower wall oi. the fleld piece when the magnet is energized and the armature is drawn upwardly to the position 01 the armature shown in switch B in Figure 1. When the links are within the armature guide sections they lie close to the flat central positions or said sections, and so long as the links are in place it is impossible for the tongues l I of the armature guide sections to become unhooked from the slots in the guide straps g, but when it is desired to remove the armature guide sections for any reason, such, for instance, as removing the coil, the guide links may be unfastened from the contact carrying member and pulled out oi! the armature guide, along with the armature, and the tongues on the armature guide sections can then be pushed inwardly to disengage them from the slots in the guide straps g. The armature guide sections can then be pulled downwardly by taking hold of their flanges II and pressing downward torelease them from engagement with the projections 9 on the guide straps.

On the contact carrying member a are shown what might be calledcontact assemblages M, each including a housing 1n, open on four sides, each housing made from a blank shown in Figure 4 and containing a spring 0 and a contact member 11, The spring may be inserted in the housing by compressing it axially and inserting it through one of the open sides of the housing and then turning it to a right angle and releasing it so that it can expand axially and press the contact piece against the outer end of the housing. Each contact piece has a squared portion n at its center which extends through openings in opp site sides of the housing, and the spring normally bears against the central part of the contact piece and holds it against the outer end of the housing. The contact piece can be removed by turning it edgewise in the housing and then drawing it outward through one of the openings.

Stationary contacts 25-29 and 25--29' for the switches are shown only in front view, and not in detail, and the circuits which the switches control are not shown because the switches may be used for various purposes. Neither are the circuits for the magnets shown. These circuits can be closed or opened by switches operated manually or otherwise. Where it is desirable or necessary to have only one switch closed at a time, the interlocking bar I may be provided for preventing the possibility 01 one switch being closed during the period while the other switch is closed. For this purpose the ends of the contact carrying members a and b are formed with curved surfaces 20 and 2|, respectively, on their upper sides and the centrally pivoted lev'er has rollers at its ends which engage the corresponding ends of the low field piece having upper and lower walls, the

lower wall having a gap therein, a magnetizing coil within the field piece, said coil having a central opening, strap guides on the upper and lower walls of the field piece, at each side thereof, each strap guide on the lower wall spanning the gap in said wall and each of the latter guides having an opening therein and a downward projection opposite said gap, a hollow armature guide com! prising two opposing guide sections insertable through said gap, each guide section having a flange at its lower end, said flange having a slot therein, and having a tongue extending toward said flange, said tongue adapted to interlock with the strap guide and the projection on thestrap guide adapted to enter the slot in the flange of the armature guide section when the latter is inserted upwardly through the gap in the field piece.

2. An electromagnetic switch mechanism comprising a hollow "field piece having upper and lower walls, the lower wall having a gap therein, forming pole pieces at each side of the gap, a magnetizing coil within the field piece, said coil having a central opening therethrough, a hollow armature guide within the field piece, in line with said gap and extending through the opening in said coil, said guide comprising two complemem tary parts insertable and removable through said gap and each part attached to the upper and lower walls of the magnet core, a vertically movable member above the magnet field piece, links attached to said member and extending through said armature guide, and an armature comprising a core and a head between said links, the head being pivotally connected to the links below the field piece and the core extending upwardly between the links.

3. An electromagnetic switch mechanism comprising a hollow field piece having upper and lower walls, the lower wall having a gap therein, forming pole pieces at each side of the gap, a magnetizing coil within the field piece, said coil having a central opening therethrough, a hollow armature guide within the field piece in line with said gap and extending through the opening in said coil, said guide comprising two complementary parts insertable and removable through said gap and each part attached to the upper and lower walls of the magnet core, a vertically movable member above the magnet field piece, links attached to said member and extending through said armature guide, an armature, comprising a core and a head, between said links, the head havinga central transverse bore, a'pivot pin extending through said bore and connecting the head to the links, said pin tapering from its central portion toward its ends so as to permit a limited rocking motion of the armature when the head .is drawn upwardly against the magnet pole pieces. v

JOSEPH F. FRESE.

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